Automatic door bottom sealing mechanisms are well known in the art and generally are activated by a spring biased rod or cam action link which engages the hinge jamb of a doorway when the door is shut, causing a seal to drop onto or pivot against the threshold and to move above anticipated obstructions as the door is swung open. Due to the constant presence of dust, dirt, and moisture in and around such mechanisms, it is desirable to have an automatic threshold seal comprising as few moving parts as possible, said parts having a minimum of surface areas in rubbing contact with each other.
In addition, such prior art mechanisms employing cam action parts may perform satisfactorily under ideal conditions, but tend to bend and go out of adjustment when the threshold engaging structure is forced to move against solid, foreign objects which it might inadvertently encounter.